Diarrhea is prevalent in 50-90 percent of AIDS patients. Strong evidence supports cytokines as causative agents. Thalidomide inhibits TNF-alpha production. Investigators propose that thalidomide may inhibit refractory diarrhea in AIDS by inhibition of TNF-alpha production. Investigators will compare TNF levels of GI mucosa and sera before and after 8 weeks of thalidomide use and monitor frequency of bowel movements.